Industrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder

China Industrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder, Find details about China Intelligent Dewar Cylinders, Cryogenic Cylinder from Industrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder

Model NO.
PHO
Condition
New
Transport Package
Wooden Case Packing
Specification
30~1000L
Origin
China
HS Code
73110090
Model NO.
PHO
Condition
New
Transport Package
Wooden Case Packing
Specification
30~1000L
Origin
China
HS Code
73110090
Detailed description of gas cylinders
          
Gas cylinder
As a cryogenic insulation pressure vessel, DPL (vertical) cylinders are mainly used to store and transport liquid nitrogen, liquid oxygen, liquid argon, liquid carbon dioxide or liquefied natural gas and can automatically provide continuous gas. The design of the gas cylinder has a double layer (vacuum) structure, the inner layer is used to store cryogenic liquid, and the ektexine is wrapped with multiple layers of insulation material, which has super heat insulation performance. Meanwhile, the interlayer (the space between two layers of containers) is pumped into a high vacuum to form a good insulation system.

DPL Gas Cylinder flow chart

Industrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder        Attention: When filling natural gas, adopt double safety valve and cancel inner rupture disc.
Main components of gas cylinders
 DPL Gas cylinder Each function of DPL gas cylinder is realized through the following components. In order to familiar with the function of each part and usage of the cylinder, please read this instruction carefully before operation.
Built-in carburetor: The carburetor is a built-in evaporator coil, which is installed in the interlayer of the cylinder. Open the gas valve, then the cryogenic liquid will exchange heat with the outside environment through the vaporized coil which is close to the shell, to realize the liquid-gas conversion and achieving the purpose of liquid vaporization. Under atmospheric pressure, if the demanded gas flow is below 350 CFH (9.2 m3 / h), the internal vaporizer can meet the demand of customer's continuous demand for gas, if the demanded gas flow rate is higher, several parallel cylinders need to be connected to a main pipeline or an external carburetor nee to be connected to a single cylinder to meet this demand, to avoid damage of carburetor and other components.
Supercharger: supercharger is used to ensure that there is enough driving pressure in the gas cylinder at high emission time, to rapidly press out cryogenic liquid or gas, to meet the gas demand of customers. Open the supercharging valve, and the cryogenic liquid at the bottom of the cylinder is exchanged with the outside world through the supercharging coil close to the shell. The cryogenic liquid is converted to saturated steam, and the combined pressure regulating valve returns to the gas phase space at the top of the cylinder to increase the pressure in the cylinder.

DPL cylinder valve assembly diagramIndustrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder



Note: when filling natural gas, use double safety valve and cancel inner rupture disc.
Combination control valve: this valve has the dual function of pressure regulating and solar term. When pressurized, the cryogenic liquid in the cylinder is converted to saturated steam through the pressurized coil and returns to the gas phase space at the top of the cylinder through this valve, thus providing a continuous and stable pressure to the cylinder.When using gas, the gas with high pressure in the gas phase space at the top of the cylinder will be discharged to the outside priority through this valve to avoid the product loss caused by the opening of the relief valve due to high gas pressure. Solar terms are automatic and do not require manual operation.
Gas used valve: this valve is connected with the built-in carburetor, through which the vaporized gas can be obtained. It requires a fitting to match the gas supplied by the container.
Inlet and outlet liquid valve: this valve is used to control the filling and discharge of cryogenic liquid. Users can connect the special hose with the pipe joint in front of the valve to conduct the filling and discharge of gas cylinders.
Pressure increasing valve: this valve controls the built-in supercharger circuit, and opens the valve to pressurize the bottle.
Discharge valve: this valve is connected with the gas phase space of the cylinder. Opening this valve can release the gas in the cylinder and reduce the pressure.The valve also has overflow valve function.
Pressure gauge: shows cylinder liner pressure in pounds per square inch (psig) or kilopascals (kPa).
Liquid level indicator: the cylinder level indicator is a spring level gauge with floating rod, which can approximately indicate the capacity of cryogenic liquid in the cylinder by using the buoyancy of cryogenic liquid.But for accurate measurement, you have to weigh it.
Safety device: the cylinder liner is designed with a first-level safety valve and a second-level bursting disc, which can protect the cylinder in case of overpressure.(in the case of overpressure) the relief valve is opened to dissipate the pressure rise caused by the normal heat leakage loss caused by the insulation layer and support, or the pressure rise caused by accelerated heat leakage under fire conditions after the vacuum of the sandwich is destroyed.In case of safety valve failure, bursting disc will open pressure relief to ensure cylinder safety.

Note: when filling natural gas, use double safety valve and cancel inner bursting disc.
Note: bursting disc can only be used once.The bursting disc must be replaced after action.It can be purchased from us.
The enclosure is protected under overpressure conditions by a vacuum plug.In the event of liner leakage (resulting in high sandwich pressure), the vacuum plug will open to relieve pressure.In case the vacuum plug leaks and leads to vacuum damage to the sandwich, sweat and frost can be found on the shell. Of course, frost or condensation at the end of the pipe connected to the bottle is normal.
Warning: never remove vacuum plug under any circumstances.

2. Safety summary
This section of the manual covers the necessary cryogenic protection knowledge. Natural gas is methane (CH4) as the main component of the hydrocarbon mixture, methane is a hydrocarbon, is a colorless, odorless gas, if a large number of inhalation of this gas, people will suffer serious injury due to lack of oxygen and even suffocation death. LNG is a category a fire hazard, so stay away from fire sources.
2.1 safety protection
• workers must wear long pants, goggles, face masks, and insulated gloves when operating. Otherwise, cold burns are likely.
• the clothes of LNG operators should be made of cotton. It is forbidden to wear chemical fiber clothes that may cause static electricity. Shoes without iron nails should be worn on the feet.
• when removing and maintaining cylinder parts, it is necessary to exhaust the liquid in the cylinder and reduce the pressure to zero, so as to avoid the residual pressure of the cylinder causing injury to personnel.
• when cylinders are used as cryogenic liquid oxygen cylinders, equipment and accessories that are compatible with the requirements for oxygen use must be used, and such equipment and accessories must meet the requirements for oxygen use.
• DPL cylinders can be moved with a supporting trolley or other tools to assist in the lifting lug on the cylinder protective ring.
• DPL cylinders must be placed vertically under all conditions, and any compression, drop, or tip over can cause fatal damage to the cylinders.
• During filling or use, the cryogenic liquid shall be prevented from spatter or overflow, and anti-freeze measures shall be taken during operation.
• No fireworks are allowed in areas where LNG bottles are maintained, filled or stored;
• Empty and relieve the pressure of the LNG bottle when removing parts for maintenance;If hot fire is involved, nitrogen replacement must be carried out and hot fire requirements must be met.
2.2 warning
• gas cylinders, valves, hoses, joints, etc. used for liquid oxygen and liquefied natural gas are strictly prohibited from cross use
• protect your eyes and exposed skin
• keep the area where the equipment is located well ventilated
• stay away from flammable or electrical sparks when filling liquid oxygen or liquefied natural gas
• do not use horizontal rolling mode to move cylinders
• do not overcharge gas cylinders

3. The operating
Before performing any operation, check the cylinder appearance to ensure that the cylinder is free of quality defects or parts defects.
3.1 cylinder operation
3.1.1 hot bottle filling
Usually we call the bottle "hot bottle" before filling the cryogenic liquid for the first time and after stopping working for more than two weeks. Since the inner part of the tank is the ambient temperature, direct filling will cause a large amount of evaporation of cryogenic liquid and cause unnecessary waste. Please fill the tank according to the following filling procedures:
1. Firstly, fill the bottle with about 20L of cryogenic liquid, close the valve and let it stand. During the process of the cryogenic liquid gasification and pressure increase, the bottle liner is cooled.
2. When the pressure in the bottle reaches the normal working pressure, the system leak detection;
3. After opening the discharge valve to reduce the pressure in the bottle, the operation can be conducted according to the liquid filling procedure of 3.3.2;
Warning: empty the bottle before filling.
Warning: before the first use of LNG gas bottle, the inner container must be evacuated or replaced with nitrogen, and the oxygen content must be ≤0.3%.
Warning: LNG can be mixed with air or oxygen to form explosive gases that will burn in case of fire, so LNG must be piped to a safe place for discharge.
3.1.2 liquid filling
The filling medium and the filling quality of the cylinder should be determined first before the cylinder is filled with cryogenic liquid. Filling quality can refer to the product specification table. To ensure accurate filling, please use the scale to measure.
1.Connect the liquid phase valve of gas cylinder with the supply source with a special delivery hose. If the liquefied natural gas is filled, connect the vent valve with the return gas device and tighten it without leakage.
2.Open the vent valve and liquid phase valve of the cylinder, then open the supply valve and start filling.
3.During the filling process, the pressure in the bottle is monitored by the pressure gauge and the discharge valve is adjusted to maintain the pressure at 68.9~103.4 kPa (10~15 psig).
4.When the required filling quality is achieved, close the liquid phase valve, vent valve and supply valve.
5.Remove the delivery hose and remove the cylinder from the scale.
Warning: do not overfill cylinders.
Warning: make sure the medium in the bottle and the filling medium before filling.
Warning: fill in a well-ventilated area, as the accumulation of gases can be very dangerous.
Note: the pressure on a fully filled bottle rises very rapidly, which can cause the relief valve to open.
Note: do not smoke immediately or be near a fire as liquid oxygen or liquefied natural gas is likely to be spilled in clothing immediately after the operation on liquid oxygen or liquefied natural gas.
Note: liquid carbon dioxide forms solid dry ice when its saturation pressure drops to 483 kPa (70 psig).Therefore, when liquid carbon dioxide is filled with dpl-175h /190H/210H/ dpw-480h gas cylinder, the carbon dioxide gas in the bottle must be pressurized before it can be filled.


DPL cylinder fluid filling flowchart
Industrial and Medical Cryogenic LNG Liquid Oxygen Nitrogen Argon Dewar Cylinder



3.1.3 liquid supply
1. Connect the cylinder inlet and outlet liquid valve with the receiving source with special delivery hose, and tighten it without leakage.
2. Open the receiving source valve, then open the inlet and outlet valve of the cylinder to start the liquid supply.
3. When the pressure in the bottle is less than the pressure of the receiving equipment, please first open the booster valve and pressurize it to 862kPa(125psig)/2068 kPa(300 psig)/ 2758 kPa(400 psig) (DPW gas cylinder is 862kPa(125psig)/2068 kPa(300 psig)) before providing liquid.
4. Close the receiving valve and inlet and outlet valve, and remove the delivery hose.
Note: the above pressure is the initial set pressure of gas cylinders. If higher pressure is needed, please press 6.4 to adjust it.

DPL cylinder liquid supply flow chart



3.1.4 single cylinder gas supply
1. Connect the cylinder gas valve with the receiving source with a special delivery hose and tighten it without leakage.
2. Open cylinder gas using a valve and booster valve to pressurize the cylinder to 862 kPa (125 psig) /2068 kPa (300 psig).
3. Open the receiving source valve to obtain continuous and stable gas (9.2m3/h).
4. Close the gas using valve, pressure valve, stop the gas supply.
5. Close the receiving source valve and remove the delivery hose.
Caution: if the required gas flow increases, the supplied gas temperature will decrease.
Note: when using natural gas, the vaporization rate of the carburetor is 6 m3/h.

A single cylinder gas body is supplied to the flowchart

3.1.5 multiple cylinder gas supply
1.Depending on the amount of gas used, the user can connect several cylinders to the carburetor.
2.Open cylinder gas using a valve and booster valve to pressurize the cylinder to 862 kPa (125 psig) /2068 kPa (300 psig) /2758 kPa (400 psig).
3.Open the receiving source valve to obtain continuous and stable gas.
4.Close the gas using valve, pressure valve, stop the gas supply.
5.Close the receiving source valve and remove the delivery hose.
Note: in order to control the air supply temperature, it is generally required to install a thermometer at the outlet of the carburetor.
Flow chart of multi-cylinder gas supply



3.1.6 liquid retention
The liquid in the bottle should be left 2~3L, so that the bottle is in a cold state and will not be turned into a "hot bottle".

4. The loading and unloading
4.1 lifting
Cylinders are designed and manufactured to withstand routine handling, but they can be damaged by rough handling.Lifting position should be shown as follows:
Note: the sling must be attached to the top lug. It is forbidden to act directly on the protective ring.                                                
Caution: during lifting, the equipment should be kept steady and avoid collision with other objects, so as not to damage cylinders.
DPL cylinder lifting schematic diagram

4.2 handling
DPL cylinders can be moved with a matching trolley or trolley to assist the handling, never allow the rolling of cylinders through a protective ring.
4.3 transportation
In order to prevent gas cylinders from moving or colliding with each other during transportation, ropes are applied to fix the equipment accordingly to ensure the safety of transportation.
4.4 store
Cylinders should be stored in a well-ventilated place and not exposed to the sun for a long time.

5. Maintenance
Read the previous safety section before repairing cylinders. Never allow operation with pressure, open the discharge valve to relieve pressure before maintenance, check your tools to ensure clean and oil-free before maintenance of liquid oxygen bottles, ensure there are no fireworks around when maintenance of liquefied natural gas bottles, and ensure there are no leakage points after each repair.
5.1 leak detection
In order to ensure the normal operation of gas cylinders, system leakage detection must be carried out regularly. You can accurately determine the leak point with the help of soapy water.
5.2 leakage maintenance
Any leakage must be repaired immediately upon discovery:
• if the thread leakage occurs in the joint pipe behind the valve, close the valve and disassemble the connection to check whether there is any damage to the thread surface. If there is no damage, clean the joint thread surface and reassemble it with the specified sealing strip;If there is obvious damage to the thread surface, please replace the joint and reassemble.
• if a leak is found at the bursting disc root of the relief valve, pressure gauge or DPL cylinder and at the joint of the combined pressure regulating valve card sleeve, the discharge valve must be opened to relieve pressure to atmospheric pressure before starting maintenance.After reinstallation, perform pressure leak detection.
Is, if the valve or valve seat leakage, please open the discharge valve, pressure to atmospheric pressure, and if the DPL booster cylinder in and out of the fluid valve, valve, the gas use valve or DPW cylinder into the liquid valve, a liquid valve, pressure valve and relief valve card sets found funnelled joint, liquid and gas in the bottle should be all empty, and then according to the globe valve installation program.
5.3 parts replacement
This section includes knowledge of cylinder maintenance and maintenance.Prior to carrying out operations in accordance with the following procedures, cylinder operation records and component assembly drawings shall be first checked and their correct positions determined according to the drawings.
Floating rod spring level indicator
Long-term use of the liquid level indicator may be due to the spring aging and the indication is not accurate, the level indicator can be re-calibrated.
1. First, empty the pressure inside the cylinder, remove the protective cover bolts and remove the protective cover.
2. Use a wrench to separate the liquid level indicator from the bottle body and take out the liquid level indicator .
3. Completely immerse the aluminum float rod of the level indicator  in water. Note that the float rod must remain vertical and not touch the side wall of the water container.
4. Liquid level indicator (specially used for liquid oxygen cylinders) is subject to the full range. If the level indicator  is not removed from the water for full range, loosen the locking nut on the lower part of the spring and turn the screw to adjust. Dip into the water to check the set value and tighten the lock nut when correct.
5. After calibration, reinstall the level indicator  after it dries up.
6. Check the seal washer before installation and replace it if there is any damage.
7. When installing, make the liquid level indicator  freely droop and keep the lead hanging. Slowly put the liquid level indicator into the gas cylinder. In order to ensure the correct position of the liquid level indicator , there is a guide ring inside the bottle. If the installation position is not accurate, it cannot be fully inserted. Please pull it out and install it again.
8. Finally tighten the connection thread and do pressure leak detection at the connection.
Caution: moisture on the liquid level indicator will freeze under the cryogenic liquid and restrict the movement of the float rod, making the indication inaccurate.
Warning: the liquid level indicator is extremely cold due to contact with cryogenic liquids. Please wear gloves to protect your skin.

The relief valve
Gas cylinder liner is a pressure vessel, safety valve as a very important safety device, can effectively ensure the safe use of gas cylinders, avoid serious consequences. The opening pressure of DPL cylinder relief valve is 1586kPa (230 psig) /2413kPa(350psig) /3448 kPa(500 psig), When the gas pressure in the cylinder exceeds this value, the relief valve will automatically open and release saturated steam to the outside to reduce the pressure in the cylinder. When the pressure is lower than the safe value, the relief valve automatically returns to the seat to close. In case of safety valve leakage, safety valve failure and safety valve calibration, please discharge or replace the valve according to the following procedures:
1.Open the discharge valve to vent the pressure in the bottle to atmospheric pressure;
2.Remove the connection between the relief valve and the joint;
3.Clean the sealing tape on the internal thread of the joint;
4.Install a new calibrated safety valve;
5.Pressurized DPL cylinders to 862 kPa (125 psig) /2068 kPa (300 psig) /2758 kPa (400 psig), for pressure leak detection at the connection.
Caution: do not repair or reset the safety valve by yourself.

5.4 Valve use and maintenance
DPL cylinder combination pressure regulating valve regulation
Users can set the pressure of the combination pressure regulating valve within the adjustment range according to their needs. This operation can be carried out directly on the gas cylinder. The specific operation methods are as follows:
1. Fill the bottle with the right amount of liquid.
2. Open the pressurizing valve to start pressurizing. After the pressure stabilizes for 1 hour, record the pressure gauge reading. This value is the current set value of the pressure regulating valve.
3. Loosen the pressure regulating valve lock nut, turn the regulating bolt clockwise to increase the setting value, and counterclockwise to decrease the setting value. When the pressure gauge reading remains stable, the pressure gauge reading will be the new setting value of the pressure regulating valve.
4. Repeat until desired value is reached, then tighten the lock nut.

Combination pressure regulating valve regulating range
modelunit
Initial set value
Adjusting Range 
DPL seriesBritish unit125 psig75-175 psig
engineering unit8.6 bar5-12 bar
metric unit862 kPa517-1207 kPa
DPL-H seriesBritish unit300 psig200-350 psig
engineering unit20.7 bar13.8-24.1 bar
metric unit2068 kPa1379-2413 kPa
DPL-U
series
British unit400 psig300-600 psig
engineering unit28 bar20.7-41 bar
metric unit2758 kPa2068-4137 kPa
Caution: the set value is increased by 206.8 kPa (30 psig) by rotating clockwise once, the set value shall not be exceeded the adjustment range.

Globe valve
The globe valve of gas cylinder may suffer mechanical wear due to long-term use, which may affect its sealing performance or other service performance. Globe valve seats are generally not damaged by replacement of handwheels or internal components.If a valve is confirmed to be defective, it shall be repaired according to the following procedures:
1. Open the discharge valve to vent the pressure in the bottle to atmospheric pressure;
2. If the valve in contact with liquid is maintained, all liquid and gas in the bottle must be emptied;
3. Remove the valve only when it is restored to normal temperature;
4. Remove the fixing screw, gasket, spring and sealing washer on the handwheel;
5. Remove handwheel, unscrew bonnet, remove stem and stem seal;
6. Remove the spool and bushing assembly;
7. Clean the seat to ensure that there are no contaminants and other particles in the seat and seal;
8. Replace the damaged parts and put them back in the same steps as they were disassembled.
9. Check valve for pressure leakage.
Note: valve repair parts are not provided.
Caution: do not damage the inner surface of the seat. Any surface damage may affect the sealing performance of the valve.

5.5 vacuum detection
• Vacuum failure
Between the interlayers is an efficient insulation layer, which includes high-tech insulation, vacuum and vacuum maintenance systems, which play an important role in the service life of cylinders.The high-tech insulation layer effectively prevents heat from entering the tank in the way of thermal radiation and heat conduction, and vacuum effectively prevents heat from entering the tank in the way of thermal convection.However, due to the trace gas molecules released from various materials and the trace gas molecules leaked into the sandwich, the sandwich cannot reach the absolute vacuum.A vacuum maintenance system consists of materials that can absorb small amounts of gas molecules from the vacuum space. This system can work for several years, but the suction capacity is limited.When the sandwich vacuum fails, the following phenomena may occur to the cylinder:
1. There is cryogenic liquid in the cylinder. When the booster valve is not opened, the shell temperature of the cylinder is low.
2. There is cryogenic liquid in the cylinder and frost indicating liquid level can be seen in the cylinder shell.
3. There is cryogenic liquid inside the cylinder, "sweating" phenomenon in the cylinder shell;
4. The cylinder contains cryogenic liquid, the pressure of the liner rises too fast, and the safety valve takes off frequently.
• Evaporation rate (NER) test
In summary, vacuum failure is a very rare phenomenon. Usually the vacuum system of the cylinder can be maintained for several years, during which the vacuum of the cylinder gradually decreases (at a very slow rate).If the cylinder vacuum plug is not abnormal, but the vacuum failure is suspected, the cylinder evaporation rate (NER) test shall be performed and the test results shall be compared with the evaporation rate values in the product specification table.
1. First, fill the bottle with liquid nitrogen. Fill the bottle with 1/2 to 2/3 of the total filling mass.
2. DPL cylinder closes the inlet and outlet liquid valve, pressure valve and gas use valve, DPW cylinder closes the inlet liquid valve, outlet valve and pressure valve, and opens the discharge valve to discharge gas.
3. The cylinders stand for 24 hours and are then weighed accurately, recording weight, time and date;
4. Maintain this condition for 48 hours, and then accurately weigh the cylinder again, recording the second weight, time and date;
5. Calculate the actual daily evaporation in kg/ day according to the following formula
Daily evaporation

6. Calculate the actual daily evaporation rate in % per day according to the following formula
The rate of evaporation
 Comparing the test result with the evaporation rate in the product specification table, the evaporation rate of the new cylinder less than two times is normal, and any test result greater than two times indicates that the sandwich vacuum has been or is being lost, please contact our after-sales service department.
It should be noted that the first hot bottle or gas bottle overcharge will also cause the evaporation rate is too high. In a bottle with a vacuum loss in the sandwich, the pressure inside the vessel will rise rapidly. The temperature of the cylinder shell, especially where the pipeline is concentrated and near the support, is lower than that of other parts. Whether the shell frosts or "sweats" depends on the temperature and humidity of the surrounding environment.The existence of such condensation phenomenon is not a reliable indicator to judge the existence or absence of vacuum in a gas cylinder, while the measurement of daily evaporation rate of gas cylinders is a reliable and effective method.


 
5.6 description of CO2 liquids
DPL series low-pressure cryogenic bottles manufactured by our company can be filled with CO2 liquid, while low-pressure bottles cannot be filled with CO2 liquid.
  1. Formation of solid CO2(dry ice)
When the saturated vapor pressure of the liquid drops to 70psi (483kPa), CO2 can be formed into a solid state. Therefore, when using DPL/DPW series high-pressure bottles, the pressure must be higher than this pressure to prevent the formation of solid CO2(dry ice) blocking the pipeline.
2.  CO2 liquid charging steps:
A. Connect one end of the hose connector with the inlet and outlet valve of the high-pressure cryogenic bottle;
B. Connect the other end of the hose to the corresponding valve of the storage tank containing CO2 liquid;
C. Open the pressurization valve of the high-pressure cryogenic bottle to increase the internal pressure;
D. Operate according to the operation manual of the storage tank, and open the liquid phase valve and vent valve of the storage tank;
E. Open the inlet and outlet valve of the cryogenic bottle, through which the liquid flow and pressure can be adjusted;
F. Adjust the liquid phase valve and vent valve of the storage tank to maintain the pressure in the filling line. The pressure in the equipment and filling line must be above 70pai(483kPa), otherwise the liquid will form solid CO2(dry ice) and block the line.
G. After filling, first close the valve of the storage tank, then close the inlet and outlet valve of the cryogenic bottle and the pressurizer/economizer to release pressure in the hose;
H. Remove hose.
3. Defrosting of solid CO2 (dry ice)
A. Determine the cause of pressure reduction, timely troubleshooting to prevent recurrence;
B. Connect the air source bottle filled with high-pressure CO2 gas to the frozen high-pressure cryogenic bottle;
C. Open the vent valve of the cryogenic bottle and the valve of the air source bottle, and monitor the pressure change;
Observe the pressure of the frozen cryogenic flask to reach the pressure of 60psig(4.1bar), and maintain this pressure. When the pressure gradually rises above 60psig(4.1bar), it indicates that the ice is melting and the pressure continues to rise between 200 and 300psig(13.8bar and 20.7bar).
Note: CO2 liquids may be contaminated, such as hydrocarbons, and are not easily removed from containers and parts, so cryogenic bottles used to fill CO2 liquids are not allowed to be filled with other gases.When replacing the parts on the cryogenic bottle filled with CO2 liquid, the CO2 liquid in the bottle must be removed to prevent freezing and blocking the pipeline.

5.7 Fault list
DPL cylinder fault list
The Fault Probable CauseSolution
Too high pressure or too fast boost rateless gas usedIf the daily gas use is below 2.8 cubic meters or so, the pressure will increase.Low pressure relief valve and regulator should be provided if cryogenic bottle is used for liquid supply.Normal boost should not exceed 50Psi(0.35MPa) per day.
Excessive fillingIf the filling is excessive, the pressure in the bottle may increase rapidly after the filling is completed. It is forbidden to overfill
The booster regulator is improperly set or malfunctionedAfter supercharging, the working pressure exceeds and remains above the required pressure, and the supercharger is readjusted to the required pressure
After supercharging, the working pressure keeps rising to the starting pressure of the safety valve. At the same time, if there is frost on the supercharging coil located at the bottom of the bottle body, the regulator should be replaced
Vacuum lossBottle surface appears sweat or even frost phenomenon, return to the factory for maintenance
Pressure is too lowMore gas usedPlease refer to the instruction manual and follow the recommended maximum gas consumption and pressurization capacity
Booster valve closingOpen booster valve
The booster regulator was not fully openedTest the pressurized regulator to see if it works properly at set pressure
The booster regulator set too lowAdjust the setting value of the booster regulator to the required pressure
For leaksCheck the top of the bottle for frost phenomenon or air leakage, and conduct air tightness test
Liquid temperature is too lowOpening the pressurized valve may require prolonged pressurization or external pressure
Safety valve takes off at low pressureThe starting pressure setting of safety valve is not suitable, replace the appropriate safety valve
Pressure gauge badTo renew the pressure gauge
Container full but no pressure displayPressure gauge badTo renew the pressure gauge
Damage to inner rupture discReplace the inner rupture disc
Valve close looselyRepair or replace valve
The CO2 liquid is in a condensed stateThe gas CO2 is pressurized to re-liquefy
Frost phenomenon under the bottle Pressurizing using the pressurized circuitIf the pressure in the bottle is lower than the set value of the booster regulator, this phenomenon is normal
Last charge or previous use of gasNormal phenomenon, Ice rings, or elliptic blocks of ice, often cling to bottles for days after they have been inflated or filled
The bottom of the bottle has spiral frost phenomenonThe vaporization circuit is being used to vaporize liquid into gasNormal phenomenon, should disappear within two hours after stopping to use gas
There is frost on the top of the bottleLast charge or previous use of gasNormal phenomenon
Leakage of liquid level indicatorCheck the connection of level indicator for leakage, replace the sealing gasket, reinstall, and air tightness test
Regulator line leakageTighten joint, air tightness test
Bottle body has even frost phenomenon
 
Excessive gas consumptionNormal phenomena, refer to the maximum gas use
The booster/economizer failedObserve the frosting pattern on the pressurized coil, close the pressurized valve, and replace or reset the regulator
Vacuum lossAt the same time found high speed of pressure rise and frequent safety valve jump, please contact our company, send back to the factory for repair
Some parts of the bottle have frost phenomenonInternal damage is possiblePlease contact our company and send it back to the factory for repair
Copper tube gap is too smallNormal phenomenon
Relief valve frequently openedVacuum lossPlease contact our company and send it back to the factory for repair
The safety valve is set at a low valueReset relief valve opening pressure
The air supply temperature is too lowUsed gas too muchRefer to the maximum gas usage
The liquid supply is mixed with a large amount of gasThe pressure in the bottle is higher than the suitable liquid supply pressureAdjust according to instruction manual, supply liquid at low pressure
The container is full without liquid level indicationThe aluminum rod is detached from the level indicatorRemove the level indicator, reconnect the aluminum rod, reinstall, and conduct air tightness test
The level indicator buoy is brokenReplace the buoy
The container is filled with CO2 liquid but cannot supply gasThe CO2 liquid condenses and clogs the pipelineThe gas CO2 is pressurized to re-liquefy


6. Emergency measures
6.1 Dress Code For Emergency Personnel
Contact with the cryogenic fluid through the eyes or skin can cause a cold burn similar to a burn. Be careful not to splash or spill.To the eyes, skin and other parts easy to contact with cryogenic liquid protection, wear protective glasses or face cover; Wear protective gloves and long sleeves that are easy to take off to protect your arms;Wear strapless pants with the legs over your shoes to keep out any spilled cryogenic liquid. Emergency personnel should wear cotton clothing, preferably without pockets or rolled-up parts.Do not wear chemical fiber clothes that may cause static electricity. Shoes without iron nails should be worn on the feet.
6.2 In The Fire Environment
At this point, should be timely closed all and gas, liquid phase of the same valve.When the valve cannot be closed or the leakage cannot be blocked, do not spray the liquid leakage directly with water. Dry powder (preferably potassium carbonate) fire extinguisher is recommended.
6.3 In Case Of Over-Pressure Relief
At this point, the discharge valve should be opened in time to release the overpressure gas in the bottle to the safety valve as soon as possible.When releasing oxygen or natural gas into the air, make sure that there is no fire, combustible or pedestrian passing nearby.If the reducing effect of emission gas is poor, the cylinder can be moved to the open place, connected with the conveying hose, and the inlet and outlet liquid valve (DPL cylinder)/outlet valve (DPW cylinder) can be opened when the discharge valve is emptied.
Note: emptying liquid is not allowed into the underground drain.
6.4 Accidental Leakage Of Cylinder Liner
At this time, due to internal liquid leakage, the tank is under the state of excess pressure, which will lead to and cause an accident. The liquid in the bottle should be discharged or discharged to other intact similar bottles as soon as possible. If conditions permit, the damaged bottle should be transferred to a place where there is no open fire, combustible or pedestrian passage for emergency treatment as soon as possible.
6.5 When Valve Is Frozen
If the valve is frozen, use clean oil-free warm water or hot nitrogen to defrost before operation.Do not use hammer or other objects to open forcibly.